Mats Hummels was late only once. In the 59th minute of Borussia Dortmund’s Champions League game at AC Milan, the soon-to-be 35-year-old defender took the tackle too late that evening and Milan playmaker Ruben Loftus-Creek was through. Luckily for BVB, the Englishman wasted the attack. His attempted pass to Olivier Giroud, who was lurking in the center of the attack, was intercepted by Hummel’s defensive colleagues. It was the only scene in the time-honored Guiseppe Meazza Stadium in which the (now-again) international player got his timing wrong and underestimated the pace of his opponent.

Otherwise, Hummels was the best man of a team that, thanks to the deserved 3-1 win, secured their place in the round of 16 of the premier class. And that in the so-called hammer (or alternatively death) group. Before the season, no one really believed that BVB would prevail against the Sheik clubs Paris Saint-Germain, Newcastle United and the US investor club AC Milan. After the penultimate matchday, BVB is leading the group and has a good chance of defending its lead on the last matchday against PSG.

UEFA also saw the fact that Hummels had played an outstanding game and named him “Man of the Match”. BVB consultant Matthias Sammer, who was on site as an expert for the broadcaster Amazon Prime, was also delighted: Hummels’ performance was “world class,” enthused the otherwise grumpy Sammer. The other management staff at BVB also couldn’t get over their heads in view of the senior grandeur that the 2014 world champion conjured up on the pitch. Sports director Sebastian Kehl raved about an “outstanding performance” and coach Edin Terzić reached high on the shelf and called his defense chief “football god”.

But Terzić was right. With great strength in duels and impressive build-up play, Hummels was a key success factor on the porous pitch in Milan. And what did the protagonist of the evening say about his performance and the team’s performance? “It’s definitely a sign that we’ve grown up. Today we can be proud,” he commented. But the defender was also reminiscent of Borussia’s less convincing games in the past on the European stage. “We used to break away more often in away games like this – when things got tough.”

The first group game against PSG was such an example. The Dortmund team played anxiously and overwhelmed and lost 2-0. It was one of those performances that repeatedly raised doubts about the team’s suitability for the Champions League. As in the Bundesliga, BVB is a surprise bag that doesn’t know what will come out in the end. Hummels explicitly included himself in the criticism, as befits a gentleman player. He had been “a bit too inconsistent in the last few weeks”. In the league, Borussia have fallen behind due to fluctuations in form and are ten points behind league leaders Bayer Leverkusen and eight behind second-placed Bayern.

The team proves with great regularity that things can actually be different. Even within a game, BVB likes to show two faces. This was the case last weekend in the game against Borussia Mönchengladbach, when the team completely slept through the first 30 minutes, only to then turn a 0-2 into a 4-2. In the Champions League, the change came in the third group game against Newcastle United, when BVB defended their narrow 1-0 lead with an outstanding fight for one half. The second leg against the English was even more convincing and now against Milan the performance was also very “mature”, to use Hummels’ words. The last game in the Champions League is against PSG, which is still fighting for a place in the knockout phase. It will be interesting to see what face BVB will show.